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authorWu Fengguang <fengguang.wu@intel.com>2011-04-14 07:52:37 -0600
committerWu Fengguang <fengguang.wu@intel.com>2011-12-18 14:20:22 +0800
commitd3bc1fef9389e409a772ea174a5e41a6f93d9b7b (patch)
treed1e47354263b7c930a7ec4428909693d10a10c50 /mm/page-writeback.c
parent54848d73f9f254631303d6eab9b976855988b266 (diff)
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writeback: fix dirtied pages accounting on sub-page writes
When dd in 512bytes, generic_perform_write() calls balance_dirty_pages_ratelimited() 8 times for the same page, but obviously the page is only dirtied once. Fix it by accounting tsk->nr_dirtied and bdp_ratelimits at page dirty time. Acked-by: Jan Kara <jack@suse.cz> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Diffstat (limited to 'mm/page-writeback.c')
-rw-r--r--mm/page-writeback.c13
1 files changed, 5 insertions, 8 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 619c445..5d1ef5d 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1258,8 +1258,6 @@ void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
if (bdi->dirty_exceeded)
ratelimit = min(ratelimit, 32 >> (PAGE_SHIFT - 10));
- current->nr_dirtied += nr_pages_dirtied;
-
preempt_disable();
/*
* This prevents one CPU to accumulate too many dirtied pages without
@@ -1270,12 +1268,9 @@ void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
p = &__get_cpu_var(bdp_ratelimits);
if (unlikely(current->nr_dirtied >= ratelimit))
*p = 0;
- else {
- *p += nr_pages_dirtied;
- if (unlikely(*p >= ratelimit_pages)) {
- *p = 0;
- ratelimit = 0;
- }
+ else if (unlikely(*p >= ratelimit_pages)) {
+ *p = 0;
+ ratelimit = 0;
}
/*
* Pick up the dirtied pages by the exited tasks. This avoids lots of
@@ -1768,6 +1763,8 @@ void account_page_dirtied(struct page *page, struct address_space *mapping)
__inc_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE);
__inc_bdi_stat(mapping->backing_dev_info, BDI_DIRTIED);
task_io_account_write(PAGE_CACHE_SIZE);
+ current->nr_dirtied++;
+ this_cpu_inc(bdp_ratelimits);
}
}
EXPORT_SYMBOL(account_page_dirtied);